CN113457192A

CN113457192A - Intelligent vacuum device

Info

Publication number: CN113457192A
Application number: CN202110657142.5A
Authority: CN
Inventors: 林蕾
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-06-12
Filing date: 2021-06-12
Publication date: 2021-10-01

Abstract

The invention relates to an intelligent vacuum device which comprises a three-way valve, a one-way valve, a temperature sensor, a pressure sensor, a vacuum pump, a screen, a room temperature sensor, a rotary evaporator heating water bath temperature sensor and a controller. The intelligent vacuum device can effectively prevent bumping, improve the recovery rate of the solvent, automatically detect the end of evaporation and close the equipment without manual supervision so as to save energy.

Description

Intelligent vacuum device

Technical Field

The invention relates to a vacuum device, belongs to the fields of medicines, foods and chemistry, and particularly relates to an intelligent vacuum device for a rotary evaporator.

Background

A rotary evaporator, also called a rotary evaporator, is common equipment in a laboratory, consists of a motor, an evaporation flask, a heating pot, a condensing tube and the like, is mainly used for continuously evaporating volatile solvents under a reduced pressure condition, and is widely applied to the fields of chemistry, chemical engineering, biological medicine and the like.

The rotary evaporator makes the evaporation flask in a negative pressure state through a vacuum pump, the evaporation flask is placed in a water bath kettle for constant temperature heating while rotating (so that the solvent forms a film and the evaporation area is increased), and the solution in the flask is heated, diffused and evaporated in the rotary flask under the negative pressure. In addition, under the action of the high-efficiency cooler, the hot steam can be quickly liquefied, and the evaporation rate is increased.

In the use of a rotary evaporator, bumping often occurs when evaporation is initiated or when new liquid is added to the evaporation flask, or as evaporation proceeds the liquid becomes more viscous. The bumping is an explosion phenomenon that saturated liquid in an equilibrium state is changed into a superheated hot body exceeding a boiling point due to too low pressure, and the saturated liquid is rapidly boiled and evaporated, and the volume is rapidly expanded. The occurrence of bumping will cause sample loss, sample contamination and even experimental failure. Therefore, people often need to stare at the system, when the bumping happens, the system is quickly deflated to release the pressure, but sometimes the bumping happens if the reaction of people is not quick enough and the pressure is not released in time.

For low-boiling-point and volatile solvents such as methanol and dichloromethane, the high-efficiency cooler often cannot completely cool the solvents, and the solvents are pumped into the pump, so that the solvent recovery rate is low, and the service life of the pump pipe is shortened due to corrosion of the organic solvent. Therefore, in practical use, the vacuum tube is clamped after the vacuum pumping reaches a certain vacuum degree, the vacuum tube clamp is released after a period of time, the vacuum tube is continuously pumped, and then the vacuum tube is clamped, and the steps are repeated so as to reduce the solvent entering the pump system and improve the recovery rate of the solvent.

In order to ensure that the sample is completely evaporated, usually a high-efficiency cooler is used to have no liquid dripping, and the state of the sample is observed to judge whether the sample is evaporated to dryness by experience, sometimes additional vacuum drying is performed for a certain time in order to ensure that the sample is completely evaporated to dryness, and this processing mode causes a certain difference in evaporation time between batches, and for the thermally unstable sample, the difference of related substances between batches is large, and the process stability is poor.

During the experiment, the condition of outage happens occasionally, and at this moment, because be in the negative pressure in the rotatory evaporimeter system, the medium of vacuum pump will be inhaled in the rotatory evaporimeter backward, causes the sample serious pollution, even the experiment failure. Sometimes, due to mismatching of the evaporation flask or due to the fact that the sample is separated out from the evaporation flask opening, the evaporation flask and the interface cannot be well matched, and a system leaks air, at the moment, the phenomenon that the vacuum degree is not available for a long time is often observed for judgment, the evaporation flask opening is cleaned and then connected to be restarted, if the vacuum degree is still unavailable for a long time, the reason needs to be continuously checked, and the sample is heated for a long time additionally.

Patent 201810478812.5 provides a device that can monitor the automatic anti-bumping of rotatory evaporimeter, through the image of taking the evaporation flask in, discerns the image, monitors the emergence of bumping, opens the valve and releases the vacuum when the emergence bumping and handles. Since the bumping occurs in a moment, it is difficult to completely avoid the bumping in this way, and if a certain sample is concentrated previously, the wall of the evaporating flask will be filled with the sample paste, at which time the condition inside the flask is difficult to observe visually.

Patent 201810516575.7 provides an automatic anti-bumping device of rotary evaporator, which is characterized in that a floating ball is lifted by bumping air bubbles when bumping, and when the floating ball appears, the floating ball is released for processing by image recognition. This treatment is also carried out after bumping has occurred, which makes it difficult to completely avoid bumping.

Patent 201220465695.7 provides a rotary evaporator pressure control device, parallelly connected a governing valve between vacuum pump and evaporation flask, changes the speed that gaseous entering rotary evaporator in through manual governing valve, changes the pressure in the evaporation flask, improves solvent recovery, reduces the possibility that bumping leads to the experiment failure. This approach does not predict bumping and requires manual attention, whereby a quick manual unscrewing of the valve releases the vacuum when bumping is observed, but bumping often occurs in a moment, with little attention or a human reaction not being rapid enough, and bumping often still occurs.

Patent 201320095276.3 provides a vacuum controller for a rotary evaporator, a buffer bottle is connected in parallel between a vacuum pump and the rotary evaporator, a pressure gauge and a throttle valve are arranged on the buffer bottle, and the throttle valve is opened to the maximum first and then slowly closed to reach a proper vacuum degree. The processing mode has poor applicability to the mixed solvent, the boiling point of the mixed solvent can be greatly changed and still generate bumping along with the early evaporation of low-boiling-point and volatile solvents (such as ethanol and ethanol in water) in the mixed solvent (such as the mixed solvent of ethanol and water), and the concentration of a sample is increased along with the concentration of the sample, the viscosity of liquid is increased and the bumping also occurs, and at the moment, the required vacuum degree cannot be accurately set.

Patent 201621444292.9 provides an explosion-proof formula rotary evaporator that boils, caches boiling liquid through set up the buffer bottle above the evaporation flask to destroy the bubble that produces in boiling out the solvent through a plurality of archs, slow down the explosive boiling. This method of treatment still makes it difficult to avoid the highly explosive liquid (e.g. containing surfactant) from popping and rushing out of the buffer bottle.

Patent 201921968924.5 provides a can avoid the rotatory evaporator that low boiling solvent explodes and boils, nests the metal heat dissipation cover on the evaporation flask, through the temperature of cooling bumping liquid, slows down the bumping when taking place to explode and boil. When the explosion boiling happens, the explosion boiling is often flushed out instantly, but the explosion boiling does not overflow along the bottle wall, and the bottle wall is cooled at the moment, so the effect is limited, and the explosion boiling cannot be completely avoided.

Disclosure of Invention

Aiming at the defects of the existing processing mode, the invention aims to provide an intelligent vacuum device which can monitor the pressure in a system, draw a pressure curve, predict the occurrence of bumping through the current real-time pressure curve, immediately release vacuum when bumping occurs, avoid bumping, set a pressure maintaining interval for a volatile solvent, keep the vacuum degree in the set interval by adjusting the pump speed, greatly improve the recovery rate of the volatile solvent, automatically detect evaporation to dryness, remind a user and avoid suck back through a one-way valve when unexpected power failure occurs.

In order to achieve the purpose, the invention adopts the following technical scheme:

an intelligent vacuum device comprises a three-way valve, a one-way valve, a temperature sensor, a pressure sensor, a vacuum pump, a screen and a controller, wherein the three-way valve selects a vacuum pumping interface of a rotary evaporator, releases a vacuum air inlet and the conduction direction of the vacuum pump of the device, the one-way valve allows airflow to flow to the vacuum pump and prevents media in the vacuum pump from flowing back, the temperature sensor monitors the temperature in a pipeline, the pressure sensor monitors the pressure in the pipeline, the vacuum pump is used as power for pumping vacuum, a user of the screen receives input parameters of the user, the controller controls the speed of the vacuum pump according to the pressure set by the user, stably and peacefully controls the vacuum degree during evaporation, improves the recovery rate of a solvent, and the controller calculates the vacuum degree during boiling of the solvent through an algorithm according to the input of the temperature sensor and the pressure sensor, and drawing a real-time pressure curve, predicting the occurrence of the bumping, and releasing vacuum in time to avoid the occurrence of the bumping.

Preferably, the intelligent vacuum device further comprises a room temperature sensor for measuring the room temperature of the environment where the device is located.

Preferably, the intelligent vacuum device further comprises a rotary evaporator heating water bath temperature sensor, and the temperature sensor is used for measuring the temperature of the rotary evaporator heating water bath.

Preferably, the controller controls the evaporation process as follows: if the user selects to maintain the set pressure for evaporation, the controller controls the speed of the vacuum pump to keep the vacuum pressure within the range of the set pressure of the user and continuously evaporate; if the user selects intelligent evaporation, the controller monitors the reading Tp of the temperature sensor and the ambient room temperature Tm in the vacuum evaporation process, when Tp > (Tm + threshold value) indicates that the solvent is not cooled in time and is pumped into the pipeline, so that the vacuum degree is too high, the controller reduces the speed of the vacuum pump to reduce the vacuum degree, and the evaporation with the maximum efficiency is kept; no matter which mode is selected by a user, the controller draws a real-time pressure-time curve, when the change rate of the pressure along with the time exceeds an inflection point threshold value, the sudden rise of the pressure (bumping phenomenon) is indicated, and at the moment, the controller immediately controls the three-way valve to lead to the air to release the pressure in the rotary evaporator system, so that the bumping is eliminated.

Preferably, the controller determines the end of evaporation as follows: when the solvent is evaporated to dryness, a large amount of solvent is not volatilized any more, the output power of the vacuum pump is required to maintain the vacuum degree, the set vacuum degree can be maintained when the vacuum pump maintaining speed is low, the controller determines that the evaporation is finished within a certain time period according to the fact that the vacuum pump maintaining speed is lower than the set threshold value, the controller controls the three-way valve to release the vacuum after the time set by a user is continuously evaporated, and the vacuum pump is closed.

Preferably, the vacuum pump adopts a circulating water pump, an organic solvent sensor is arranged in the water medium of the vacuum pump, and when the content of the organic solvent in the water medium of the vacuum pump exceeds a threshold value, a user is prompted to replace the water medium in time so as to protect the vacuum pump.

Has the advantages that:

(1) the invention can predict the bumping according to the real-time pressure-time curve, and prevent the bumping by releasing the pressure in the system in time.

(2) The invention keeps the vacuum degree stable during evaporation by adjusting the speed of the vacuum pump, avoids the vacuum degree fluctuation of the conventional valve control type evaporation and greatly improves the solvent recovery rate.

(3) According to the invention, when power is cut off accidentally, the one-way valve prevents the medium of the vacuum pump from flowing back into the rotary evaporator, so that the sample in the rotary evaporator is protected.

(4) The invention can automatically detect the completion of evaporation, execute the extra evaporation time set by a user to ensure the complete evaporation, automatically release the pressure and stop the vacuum pump to prompt the user to finish the evaporation, and ensure the relative consistency of the evaporation time of each batch of samples, thereby improving the consistency among batches.

Drawings

FIG. 1 is a schematic diagram of an embodiment of an intelligent vacuum apparatus according to the present invention.

In the figure: 1. the device comprises a connecting pipeline for a vacuum pumping interface of the rotary evaporator and the device, 2, a release air inlet, 3, a three-way valve, 4, a one-way valve, 5, a temperature sensor, 6, a pressure sensor, 7, a vacuum pump, 8, a controller, 9, a screen, 10, a room temperature sensor, 11, a heating water bath temperature sensor of the rotary evaporator, 12, a condenser pipe of the rotary evaporator, 13, a solvent receiving bottle of the rotary evaporator, 14, an evaporation flask of the rotary evaporator, 15 and a heating water bath of the rotary evaporator.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The first embodiment is as follows:

as shown in fig. 1, an intelligent vacuum device comprises a three-way valve, a one-way valve, a temperature sensor, a pressure sensor, a vacuum pump, a screen, a room temperature sensor, a rotary evaporator heating water bath temperature sensor and a controller.

The controller first reads the user set pressure Ps and the user selected control mode (maintenance set pressure evaporation mode and smart evaporation mode). The controller measures the ambient room temperature Tm of the room temperature sensor (10) and the heating water bath temperature Tw of the heating water bath temperature sensor (11) of the rotary evaporator, and determines whether the user adopts non-heating evaporation (Tw is less than or equal to Tm, room temperature evaporation, even low temperature evaporation) or heating evaporation (Tw > Tm).

The controller continuously monitors the temperature Tp of the temperature sensor (5) and the pressure Pr of the pressure sensor (6) in the evaporation process, draws a real-time pressure-time curve, and calculates the time-dependent rate of change of the pressure DeltaP/Deltat.

The controller performs one of the following modes of operation based on user settings and sensor readings:

(1) non-heating evaporation, maintaining a set pressure evaporation mode: in the mode, a user can only select an evaporation mode for maintaining the set pressure, and the controller controls the speed of the vacuum pump (7) through a proportional-integral-derivative (PID) algorithm to maintain the pressure at the set pressure of the user for continuous evaporation;

(2) heating and evaporating, and maintaining a set pressure evaporation mode: the controller controls the speed of the vacuum pump (7) through a PID algorithm to maintain the pressure at the pressure set by a user and continuously evaporate;

(3) heating evaporation, intelligent evaporation mode: in this mode the controller monitors the difference Δ T = (Tp-Tm) between Tp and Tm, when Δ T exceeds a specified threshold indicating that the vacuum is too high resulting in insufficient condensation of steam causing steam to be drawn into the vacuum line, the controller reduces the vacuum to reduce excessive evaporation, otherwise, the controller continues to maintain vacuum to maintain the most efficient evaporation;

no matter which operation mode is adopted, the controller predicts the occurrence of the bumping by monitoring the time change rate delta P/delta t of the pressure, when the delta P/delta t exceeds an inflection point threshold value, the sudden rise of the pressure (bumping phenomenon) is shown, at the moment, the controller immediately controls the three-way valve (3) to be communicated with the air (2) to release the pressure in the rotary evaporator system, so that the bumping is eliminated, and then the controller controls the three-way valve (3) to be communicated with the one-way valve (4) to continue the vacuum pumping operation.

When the speed of the vacuum pump (7) is lower than the threshold value and is maintained for a certain time, the vacuum pump is indicated to maintain low output power, the vacuum degree can be kept, namely, a large amount of solvent is not evaporated, the vacuum pump is required to work to maintain the vacuum degree, the evaporation is indicated to be nearly finished, at the moment, after the controller maintains a period of time set by a system working user, the three-way valve (3) is controlled to be communicated with the air (2) to release the vacuum in the system, the vacuum pump (7) is closed, and the user is prompted to finish the evaporation.

And (3) experimental test:

the ethanol extract of the Chinese medicine radix bupleuri is used for carrying out evaporation concentration test, the radix bupleuri extract is divided into three parts, each part is 500 mL, evaporation concentration is respectively carried out according to the following modes, the solvent recovery rate, the evaporation time and the bumping condition of each mode are examined, and the results are as follows:

(1) the vacuum pump of the invention works in an intelligent evaporation mode:

recovering the solvent amount: 450 mL (90.0% recovery);

evaporation time: 1h03 min;

the occurrence of bumping: no bumping occurred.

(2) The vacuum pump of the invention is adopted to work in an evaporation mode (set pressure-0.08 MPa):

recovering the solvent amount: 420 mL (84.0% recovery);

evaporation time: 1h and 47 min;

the occurrence of bumping: no bumping occurred.

(3) A commercially available vacuum pump is adopted, and evaporation is carried out by artificial supervision and control:

recovering the solvent amount: 260 mL (41.2% recovery);

evaporation time: 3h and 20 min;

the occurrence of bumping: several times of explosive boiling occur at the beginning of evaporation, all the explosive boiling is decomposed through artificial deflation, when the liquid medicine is evaporated to the rest half, the explosive boiling occurs again because the liquid medicine becomes viscous, the air release is not achieved, the mother liquid is flushed into the solvent receiving bottle through explosive boiling, the liquid in the solvent receiving bottle can only be poured back into the evaporation flask for re-evaporation, and therefore the experimental time is long.

The result shows that the vacuum pump effectively avoids the occurrence of bumping, the recovery rate of the solvent is obviously higher than that of the conventional valve-controlled distillation, and the evaporation time is shorter.

Claims

1. An intelligent vacuum device comprises a three-way valve, a one-way valve, a temperature sensor, a pressure sensor and a vacuum pump, wherein the three-way valve selects a vacuumizing interface of a rotary evaporator, a vacuum air releasing inlet and the conduction direction of the vacuum pump of the device; the method is characterized in that: this intelligence vacuum apparatus still includes: and the controller is used for controlling the evaporation process.

2. The intelligent vacuum apparatus of claim 1, wherein: the intelligent vacuum device also comprises a screen, and a user receives user input parameters and a control mode.

3. The intelligent vacuum apparatus of claim 1, wherein: the intelligent vacuum device further comprises a room temperature sensor and an external temperature sensor, wherein the room temperature sensor is used for measuring the room temperature of the working environment where the device is located, and the external temperature sensor is used for measuring the temperature of a heating water bath of a rotary evaporator combined with the device.

4. An intelligent vacuum apparatus as claimed in any one of claims 1-3, wherein: the intelligent vacuum device monitors the occurrence of the bumping by drawing a real-time pressure-time curve, and immediately releases the pressure in the system through the three-way valve when the bumping occurs, so as to avoid the bumping.

5. An intelligent vacuum apparatus as claimed in any one of claims 1-3, wherein: the intelligent vacuum device controls the speed of the vacuum pump through a proportional-integral-derivative (PID) algorithm to realize the stable and peaceful control of the vacuum degree during evaporation.

6. An intelligent vacuum apparatus as claimed in any one of claims 1-3, wherein: the intelligent vacuum device determines the end of evaporation by monitoring the speed and the real-time pressure of the vacuum pump, automatically releases vacuum and stops the vacuum pump from working.